I have tried looking at the details of the /dev/main log
cat /dev/log/main | grep wpabut I don't see anything obvious. To me it looks like there is some type of failure that puts it back into scanning mode.
The original version of wpa_supplicant is version 0.6.10. I don't know if a new version of this must be patched to work right. If someone has a non-wifi only version of the system and can get the version number of their original wpa_supplicant file this might yield some information.